This research proposal has as its goal the isolation, purification and biochemical characterization of the mucin-type and membrane-associated glycoproteins of the large intestine of experimental animals and man. Goblet cell mucus from human and animal colons will be purified by ultracentrifugation and gel filtration. The carbohydrate content, glycopeptide composition and sub-unit structure will be determined using gas-liquid chromatography, ion-exchange chromatography and polyacrylamide gel electrophoresis. The physical properties of purified mucus gel will be studied under various in vitro conditions and correlated with the biochemical structure. The factors which organ culture, and in vivo in experimental animals. We will test the effects of bacterial toxins, bile salts, gut hormones and cyclic nucleotides on goblet cell secretion from the colon. The membrane associated glycoproteins of colonic epithelial cells will be isolated from organ culture experiments and from experimental animals after injection of radioactive monosaccharide precursors. The membrane glycoproteins will be purified using gel filtration, lectin affinity chromatography and ion-exchange chromatography. We will label externally located cell surface glycoproteins using non-penetrating reagents such as lactoperoxidase or galactose oxidase-sodium borohydride. These labelled glycoproteins can then be purified and characterized by chromatographic and electrophoretic techniques. Autoradiographic studies will be used to confirm the external membrane location of surface glycoproteins labelled in this fashion. Colonic glycoprotein synthesis and secretion will be compared in normal individuals and patients with chronic inflammatory bowel disease. Mucus and membrane associated glycoproteins will be isolated from colectomy specimens and from organ culture experiments. The glycoproteins will be characterized by the methods outlined above in order to determine if there are significant alterations, either quantitive or qualitative, in colonic glycoprotein metabolism in chronic inflammatory bowel disease.